Java：如何清除和排序 .txt 文件中的所有内容？

Question

1. How can i sort all of my string content in .txt file based on alphabetical? For example : here's what inside the txt file :

   1. Jhon
   2. Anna
   3. Alice

   After sorting :

   1. Alice
   2. Anna
   3. Jhon
2. How would i clear all of the contents and leave only the empty txt file?

Answer 1

public static void main(String[] args){
    try {
        File file = new File("input.txt")
        List<String> allLines = Files.readAllLines(file.toPath(), Charset.defaultCharset());
        Collections.sort(allLines);

        //For deleting
        file.delete();
        file.createNewFile();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

Answer 2

For example

File file = new File("filepathname.txt");
file.delete();
file.creatFile();

Answer 3

File myFile = null;
BufferedReader br = null;
BufferedWriter bw = null;
String [] name = {
"John"," AnNa","1","AliCe",
"Ammy"," JOey","Alex","0"};

try {
myFile = new File("unsorted strings.txt");
myFile.createNewFile();
bw = new BufferedWriter(new FileWriter(myFile));

for ( int i = 0; i < name.length; i++ ){
bw.write(name[i]);
bw.newLine();
}

bw.close();
br = new BufferedReader(new FileReader(myFile));
String temp = "";
int counter = 0;

while((temp = br.readLine()) != null){
//temp = temp.trim();
//char fChar = temp.toUpperCase().charAt(0);
//temp = temp.substring(1,temp.length()).toLowerCase();
//name[counter] = fChar + temp;
//counter++;

name[counter] = temp;
counter++;
}

br.close();

//java.util.Arrays.sort(name);

java.util.Arrays.sort(name,new java.util.Comparator< String >(){
public int compare(String o1, String o2) {
return o1.trim().toLowerCase().compareTo(o2.trim().toLowerCase());
}});


myFile = new File("sorted strings.txt");
myFile.createNewFile();
bw = new BufferedWriter(new FileWriter(myFile));


for ( int i = 0; i < name.length; i++ ){
bw.write(name[i]);
bw.newLine();

}


bw.close();

myFile = new File("empty file.txt");
myFile.createNewFile();
bw = new BufferedWriter(new FileWriter(myFile));
bw.write("");
bw.close();

}catch (Exception ex) {
ex.printStackTrace();
}